Mark Boslough, University of New Mexico

With the Taurid meteor shower now hitting the night skies worldwide, look for what could be a celestial treat – you might see shooting stars, and maybe even fireballs, the biggest and brightest meteors.

As the full moon begins to wane after Nov. 15, the sky will be darker, due to diminishing moonlight, so finding the meteors will get easier. That said, the best visibility for the meteors through the rest of the month will come just before moonrise each night.

Beyond the light show, there is something else that scientists as well as onlookers have long wondered about: the possibility that bigger chunks are in the Taurid meteor streams, chunks the size of boulders, buildings or even mountains.

And if that’s true, could one of those monster-sized Taurid objects collide with Earth? Could they wipe out a city, or worse? Is it possible that’s already happened, sometime in our planet’s past?

As a physicist who researches the risk that comets and asteroids pose to the Earth, I’m aware that this is a subject where pseudoscience often competes with actual science. So let’s try to find the line between fact and fiction.

Pig Pen, glowing tails and shooting stars

Comet Encke is the so-called parent comet of the Taurid meteors. It’s relatively small, just over 3 miles (almost 5 kilometers) in diameter, and crosses inside Earth’s orbit and back out every 3.3 years.

As Encke moves, it sheds dust wherever it goes, like the Peanuts character Pig Pen. A meteor shower occurs when that dust and debris light up while entering Earth’s atmosphere at high speeds. Ultimately, they vanish into an incandescent puff of vapor with a glowing tail, creating the illusion of a “shooting star.”

But dust isn’t all that breaks off the comet. So do bigger chunks, the size of pebbles and stones. When they collide with the air, they create the much brighter fireballs, which sometimes explode.

Doomsday showers

The “coherent catastrophism” hypothesis suggests that comet Encke was created when an even larger comet broke up into pieces; Encke survived as the largest piece. The hypothesis also suggests that other mountain-sized chunks broke off and coalesced into a large swarm of fragments too. If such a swarm exists, there is a possibility that those large chunks could one day hit Earth as it passes through the swarm.

But just because something might be physically possible doesn’t mean that it exists. Mainstream astronomers have rejected this theory’s most catastrophic predictions. Among other reasons, scientists have never observed high concentrations of these mountain-sized objects.

Despite the lack of evidence, researchers on the fringes of science have embraced the idea. They claim the Earth experienced a global catastrophic swarm 12,900 years ago; the impact, they say, caused continent-wide firestorms, floods and abrupt climate change that led to the mass extinction of large mammals, such as woolly mammoths, and the disappearance of early Americans known as the Clovis people.

The evidence for a catastrophic cause of these events, most of which did not happen, is lacking. Nevertheless, the idea has gained a large following and formed the basis for British author Graham Hancock’s popular TV series, “Ancient Apocalypse.”

The Tunguska event

But even outlandish ideas can have elements of truth, and there are hints that some objects – more than just dust and debris, but less than doomsday size – indeed exist in the Taurid meteor stream, and that the Earth has already encountered them.

One clue comes from an event on June 30, 1908, when an enormous explosion in the sky blew down millions of trees in Siberia. This was the Tunguska event – an airburst from an object that may have been up to 160 feet (about 50 meters) in diameter.

The collision unleashed several megatons of energy, which is roughly the equivalent of a large thermonuclear bomb. What happens is this: The incoming object penetrates deep into Earth’s atmosphere, and the dense air slows it down and heats it up until it vaporizes and explodes.

Could this object have been a Taurid? After all, the Taurids cross Earth’s orbit twice a year – not just in autumn, but also in June.

Here’s the evidence: First, the descriptions of the trajectory of the Tunguska airburst, as reported by eyewitness observers, is consistent with that of an object coming from the Taurid stream.

What’s more, the pattern of blast damage on the ground beneath an airburst depends on the trajectory of the exploding object. Supercomputer simulations show that the shape of the surface blast that would be caused by an exploding Taurid object matches the pattern of fallen trees at Tunguska.

Finally, during the Taurid meteor shower in 1975, people observed large fireballs – and seismometers, previously placed on the Moon by Apollo astronauts, detected seismic events on the lunar surface. Scientists interpreted those events as impacts, presumably made by the Taurid meteors.

In 2032 and 2036, the Taurid swarm – assuming it exists – is predicted to be closer to the Earth than any time since 1975. That might mean the Moon, and perhaps the Earth, could be pelted again in those years.

There is time to figure this out. Scientists can expand their astronomical surveys to look for Tunguska-sized objects at the locations where they are predicted to be the next time they are in our vicinity.

Most scientists remain skeptical that such a swarm exists, but it’s the job of planetary defenders to investigate possible threats, even if the risk is small. After all, a Tunguska-sized object could conceivably demolish a major city and kill millions; an accurate count of objects on a potential collision course is essential.

Put doomsday scenarios and ancient apocalypses aside. The real question, and still an open one, is whether a Taurid swarm could deliver more Tunguska-sized objects than would otherwise be expected. This would mean we have underestimated the risk from future airbursts.

Mark Boslough, Research Associate Professor of Earth and Planetary Sciences, University of New Mexico

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sarguru Subash, Texas A&M University

Millions of people in the U.S. and around the world suffer from urinary tract infections every year. Some groups are especially prone to chronic UTIs, including women, older adults and some veterans.

These infections are typically treated with antibiotics, but overusing these drugs can make the microbes they target become resistant and reduce the medicines’ effectiveness.

To solve this problem of chronic UTIs and antibiotic resistance, we combined our expertise in microbiology and engineering to create a living material that houses a specific strain of beneficial E. coli. Our research shows that the “good” bacteria released from this biomaterial can compete with “bad” bacteria for nutrients and win, dramatically reducing the number of disease-causing microbes.

With further development, we believe this technique could help manage recurring UTIs that do not respond to antibiotics.

Bringing bacteria to the bladder

For the microbes living in people, nutrients are limited their presence varies between different parts of the body. Bacteria have to compete with other microbes and the host to acquire essential nutrients. By taking up available nutrients, beneficial bacteria can stop or slow the growth of harmful bacteria. When harmful bacteria are starved of important nutrients, they aren’t able to reach high enough numbers to cause disease.

Delivering beneficial bacteria to the bladder to prevent UTIs in challenging, though. For one, these helpful bacteria can naturally colonize only in people who are unable to fully empty their bladder, a condition called urinary retention. Even among these patients, how long these bacteria can colonize their bladders varies widely.

Current methods to deliver bacteria to the bladder are invasive and require repeated catheter insertion. Even when bacteria are successfully released into the bladder, urine will flush out these microbes because they cannot stick to the bladder wall.

Biomaterials to treat UTIs

Since beneficial bacteria cannot attach to and survive in the bladder for long, we developed a biomaterial that could slowly release bacteria in the bladder over time.

Our biomaterial is composed of living E. coli embedded in a matrix structure made of gel. It resembles a piece of jelly about 500 times smaller than a drop of water and can release bacteria for up to two weeks in the bladder. By delivering the bacteria via biomaterial, we overcome the need for the bacteria to attach to the bladder to persist in the organ.

We tested our biomaterial by placing it in human urine in petri dishes and exposing it to bacterial pathogens that cause UTIs. Our results showed that when mixed in a 50:50 ratio, the E. coli outcompeted the UTI-causing bacteria by increasing to around 85% of the total population. When we added more E. coli than UTI-causing bacteria, which is what we envision for future development and testing, the proportion of E. coli increased to over 99% of the population, essentially wiping out the UTI-causing bacteria. Moreoever, the biomaterial continued releasing E. coli for up to two weeks in human urine.

Our findings suggest that E.coli could stick around and survive in the bladder for extended periods of time and successfully decrease the growth of many types of bacteria that cause UTIs.

Improving biomaterials

Our findings show that E. coli can not only control harmful bacteria it’s closely related to but also a broad range of disease-causing bacteria in humans and animals. This means scientists might not need to identify different types of beneficial bacteria to control each pathogen – and there are many – that can cause a UTI.

Our team is currently evaluating how effectively our biomaterial can cure UTIs in mice. We are also working to identify the specific nutrients that beneficial and harmful bacteria compete over and what factors may help beneficial bacteria win. We could add these nutrients to our biomaterial to be released or withheld.

This research is still at an early stage, and clinical uses are not in development yet, so if it does reach patients it will be well in the future. We hope that our technology could be refined and applied to control other bacterial infections and some cancers caused by bacteria.

Sarguru Subash, Assistant Professor of Veterinary Pathobiology, Texas A&M University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Pamela L. Geller, University of Miami

When I started my research on the Samuel George Morton Cranial Collection, a librarian leaned over my laptop one day to share some lore. “Legend has it,” she said, “John James Audubon really collected the skulls Morton claimed as his own.” Her voice was lowered so as not to disturb the other scholars in the hushed archive.

As my work progressed, I uncovered no evidence to substantiate her whispered claim. Audubon had collected human skulls, several of which he then passed on to Morton. But birds and ornithology remained Audubon’s passion.

Nevertheless, the librarian’s offhanded comment has proven useful – a touchstone of sorts that continues to remind me of the controversy and confusion long surrounding the Morton Collection.

Morton was a physician and naturalist who lived in Philadelphia from 1799 until the end of his life in 1851. A lecture he delivered to aspiring doctors at the Philadelphia Association for Medical Instruction outlined the reasons for his cranial compulsion:

“I commenced the study of Ethnology in 1830; in which year, having occasion to deliver an introductory lecture on Anatomy, it occurred to me to illustrate the difference in the form of the skull as seen in the five great races of men … When I sought the materials for my proposed lecture, I found to my surprise that they could be neither bought nor borrowed.”

He would go on to acquire almost 1,000 human skulls.

Morton used these skulls to advance an understanding of racial differences as natural, easily categorizable and able to be ranked. Big-brained “Caucasians,” he argued in the 1839 publication “Crania Americana,” were far superior to small-skulled American Indians and even smaller-skulled Black Africans. Many subsequent scholars have since thoroughly debunked his ideas.

Certainly, condemnation of Morton as a scientific racist is warranted. But I find this take represents the man as a caricature, his conclusions as foregone. It provides little insight into his life and the complicated, interesting times in which he lived, as I detail in my book “Becoming Object: The Sociopolitics of the Samuel George Morton Cranial Collection.”

My research demonstrates that studies of skulls and diseases undertaken by Morton and his medical and scientific colleagues contributed to an understanding of U.S. citizenship that valued whiteness, Christianity and heroic masculinity defined by violence. It is an exclusionary idea of what it means to be American that persists today.

Yet, at the same time, the collection is an unintended testament to the diversity of the U.S. population during a tumultuous moment in the nation’s history.

Men of science and medicine

As a bioarchaeologist who has studied the Morton Collection for many years, I have sought to better understand the social, political and ideological circumstances that led to its creation. From my work – analyzing archival sources including letters, laws, maps and medical treatises, as well as the skulls themselves – I’ve learned that, over a lifetime, Morton fostered a professional network that had far-reaching tentacles.

He had plenty of help amassing the collection of skulls that bears his name.

The physician connected with medical colleagues – many of whom, like him, received degrees from the University of Pennsylvania – gentleman planters, enslavers, naturalists, amateur paleontologists, foreign diplomats and military officers. Occupational differences aside, they were mostly white, Christian men of some financial means.

Their interactions took place during a pivotal moment in American history, the interlude between the nation’s revolutionary consolidation and its violent civil unraveling.

Throughout this stretch of time, Morton and his colleagues catalyzed biomedical interventions and scientific standards to more effectively treat patients. They set in motion public health initiatives during epidemics. They established hospitals and medical schools. And they did so in the service of the nation.

Not all lives were seen as worthy of these men’s care, however. Men of science and medicine may have fostered life for many, but they also let others die. In “Becoming Object,” I track how they represented certain populations as biologically inferior; diseases were tied to nonwhite people, female anatomy was pathologized, and poverty was presumed inherited.

From person to specimen

Such representations made it easier for Morton and his colleagues to regulate these groups’ bodies, rationalize their deaths and collect their skulls with casual cruelty from almshouse dissecting tables, looted cemeteries and body-strewn battlefields. That is, a sizable portion of the skulls in Morton’s collections were not culled from ancient graves but belonged to those of the recently alive.

It is no coincidence that Morton began his scientific research in earnest the same year Andrew Jackson signed the Indian Removal Act of 1830. Men of science and medicine benefited from the expansionist policies, violent martial conflicts and Native displacement that underpinned Manifest Destiny.

The collection reveals these acts of nation-building as necropolitical strategies – techniques used by sovereign powers to destroy or erase certain, often already vulnerable, populations from the national consciousness. These skulls attest to precarious existences, untimely deaths and trauma experienced from cradle to beyond the grave.

In the specific case of Native Americans, skeletal analysis testifies to the violent effects of U.S. military campaigns and forced removal. Native skulls that Morton labeled “warriors” have evidence of unhealed fractures and gunshot wounds. Children’s skulls bear the marks of compromised health; such pathology and their young ages at death are evidence of long-standing malnutrition, poverty and deprivation or stress.

To effectively transform subjects into objects – human beings into specimens – collected crania were ensconced in the institutional spaces of medical school lecture halls and museum storage cabinets.

There, Morton first numbered them sequentially. These numbers along with information about race, sex, age, “idiocy” or “criminality,” cranial capacity and provenance were inked on skulls and written in catalogs. Very rarely was the person’s name recorded. If used as teaching tools, Morton drilled holes to hang the skulls for display and notated them with the names of skeletal elements and features.

As dehumanizing as this process was, the Morton Collection does contain evidence of resilience and heterogeneous lives. There are traces of people with mixed-race backgrounds such as Black Indians. Several people may have also bent gender to navigate dire conditions or in keeping with social norms, such as native Beloved Women, who were active in warfare and political life.

What these bones mean today

As anthropologists now recognize, it is through the repatriation of the remains of the people in the Morton Collection to their descendants, among other types of reparations, that current practitioners may begin to atone for the sins of intellectual forebears. Indeed, all institutions housing legacy collections must contend with this issue.

There are other, valuable lessons – about diversity and suffering – that the Morton Collection has to impart in today’s interesting times.

The collection demonstrates that the American body politic has always been a diverse one, despite efforts of erasure by men like Morton and his colleagues. Piecing together the stories of past, disenfranchised lives – and acknowledging the silences that have made it difficult to flesh them out – counters past white nationalism and xenophobia and their current resurgence.

The collection, I believe, also urges the repudiation of violence, casual cruelty and opportunism as admirable attributes of masculinity. Valorizing men who embody these qualities has never served America well. Particularly in the mid-1800s, when Morton amassed skulls, it led to a nation divided and hardened to suffering, an unfathomable death count and the increasing fragility of democracy.

Pamela L. Geller, Associate Professor of Anthropology, University of Miami

This article is republished from The Conversation under a Creative Commons license. Read the original article.